IP解析域名-bug显示解析错误

DNS_IP/IP/gethostbyaddr.cpp

@@ -0,0 +1,49 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+
+void error_handling(const char *message);
+
+int main(int argc,char *argv[])
+{
+ int i;
+ struct hostent *host;
+ struct sockaddr_in addr;
+ if(argc!=2){
+ printf("Usage : %s <IP>\n",argv[0]);
+ exit(1);
+ }
+
+ memset(&addr,0,sizeof(addr));
+ addr.sin_addr.s_addr=inet_addr(argv[1]);
+ host=gethostbyaddr((char*)&addr.sin_addr,4,AF_INET);
+ if(!host)
+ error_handling("gethost error");
+
+ printf("host of_name: %s \n",host->h_name);
+ for(i=0;host->h_aliases[i];i++)
+ printf("The %d host other name: %s\n",
+ i+1,host->h_aliases[i]);
+ printf("addrType: %s\n",
+ (host->h_addrtype==AF_INET)?"AF_INET":"ipv6");
+ //for(i=0;host->h_addr_list[i];i++)
+ // printf("The %d other IP: s \n",
+ //i+1,inet_ntoa(*(struct in_addr*)host->h_addr_list[i]));
+
+ //与上方相同,更容易理解
+ for (int i = 0; host->h_addr_list[i] != NULL; i++) {
+ struct in_addr addr;
+ memcpy(&addr, host->h_addr_list[i], sizeof(struct in_addr));
+ printf("The %d other IP: %s \n", i+1, inet_ntoa(addr));
+ }
+ return 0;
+}
+
+void error_handling(const char *message){
+ fputs(message,stderr);
+ fputc('\n',stderr);
+ exit(1);
+}